Underground mines possess inherent dangers to miners working in the mine. For one, air quality in underground mines is often threatened by gases released into the mine from the mined geological formation(s), and dust is typically created by equipment used during the mining process. Other occurrences, such as explosions and fires, also may compromise air quality. As a result, underground mines are equipped with air ventilation systems which draw fresh air into the mine to dilute and remove potentially harmful gases (e.g., methane) and dust. Accordingly, fresh outside air is circulated through the mine to bring breathable air to the miners and to remove the gases and dust from the mine.
The safety of the miners in the mine can be threatened if the ventilation system fails to adequately ventilate the mine due to an emergency. When mine ventilation systems fail, miners in the mine are typically evacuated from the mine until proper ventilation can be restored. However, the miners can be placed in peril if they are unable to quickly exit the mine. For example, the miners' exit route may be blocked by fire, smoke, or debris, or the miners may be too disoriented or too injured to escape. Miners trapped in an underground mine without breathable air can find themselves at great risk of substantial injury or even death.